A Sister's Plot
by sandersonsister
Summary: Umi was going to Karasuno. Her brother wasn't happy about it. He really wasn't going to be happy when he realized she was going to join the volleyball club as a manager. He was going to be even more unhappy when he finds out why. Kageyama/OC


Disclaimer: I don't own Haikyuu!

A/N: New story! With an OC...not something I've done for this fandom before. Let me know what you guys think!

"I just don't get it, Umi-chan! Why would you decide to go _there_?"

Umi rolled her eyes as she heard her older, yes note that word, _older_ brother whine yet again. "Because I want to, Tooru."

Oikawa Tooru scowled fiercely and crossed his arms over his chest. "But you've always gone to the school I went to! Why would you decide to go to Karasuno of all places?!"

 _Obviously, just to spite you,_ Umi thought, though she didn't say those words out loud. Truthfully, she had her own reasons for going to Karasuno, reasons that her older brother wouldn't like. And she didn't want to deal with his temper tantrum if she told him the truth. Not now, anyway.

"Oi! Leave her alone, Crappykawa!" Umi watched in satisfaction as her brothers' best friend, Iwaizumi Hajime, slammed his palm into the back of her brothers head. "She can attend whatever school she wants!"

"Thank you, Iwa-chan!" Umi exclaimed happily, sending said boy a wicked grin when he glared at her for the name.

"See if I help you again," Iwaizumi muttered. Umi giggled at the words. No matter how much he complained, there was no way Iwaizumi would allow Tooru to pick on her for long.

"But Iwa- _chan_!" Tooru complained and Umi winced when his voice took on a pitch that shouldn't have been humanly possible. "Umi-chan knows she shouldn't be going to Karasuno! She knows what they did to me!"

"Drama queen," Umi muttered as she made her escape to her bedroom. She heard Tooru let out an enraged wail as she did so and then whine pitifully after yet another loud smack. She wondered if Iwaizumi had used his hand this time or if he had found something to throw.

Tooru wasn't exactly wrong. In the past, Umi had attended the same primary school as Tooru, as well as his old junior high. Being three years younger, she and Tooru hadn't stepped foot in Kitagawa Daiichi at the same time, but she had realized that her brother's popularity had grown vastly from his time in primary school. Even though her brother and his friends had graduated the year before, that first day in her first year of junior high, Umi had found herself swarmed. There had been girls that claimed to be part of his 'fan club' that wanted information. There had been boys from the volleyball team, mostly third years, that wanted to talk to her.

The girls soon realized that they weren't going to find out anything from Umi and had finally left her alone. But the rumors of the great Oikawa Tooru had persisted and Umi had found more and more of her own female classmates trying to get invitations to her home so they could 'meet her family'. Boys from the volleyball team quickly realized the same thing – although Umi had grown up watching her brother play and she enjoyed the sport, she couldn't really help them. Teachers constantly compared her to Tooru – after all, he wasn't just a great volleyball player and a charismatic guy, he was also smart.

After three years of living in her brother's shadow in junior high, she had decided she didn't want to continue it throughout high school. Not when she already had to deal with it at home as well.

Not that she would ever say those words to Tooru. Tooru was a lot of things, being overly dramatic one of them, but he really was a great brother. When Umi actually got up the nerve to ask him, he always helped her with whatever she needed.

In her second year of junior high, Umi had been ecstatic to finally meet someone she could call a friend. She and Ito Nana had grown close and Umi had finally allowed her guard to drop one night when she invited the girl to stay over. She had noticed Nana's eyes fixated on Tooru the second she saw him, but hadn't really thought anything of it – he brother was good looking, so it wasn't odd that he attracted attention. But later that night, Umi had woke to find Nana missing from her room. The girl had been camped outside of Tooru's bedroom, her ear pressed against the door. When Umi confronted her later, Nana had confessed that the only reason she had come over in the first place was to talk to Tooru.

Umi had asked the girl to leave early the next morning. When Tooru questioned her about it later, Umi had finally confessed. Through her tears, she told him how the girls at school only spoke to her if it was about Tooru, how the boys only talked to her about volleyball. That the teachers expected her to be like him. That she didn't feel like she belonged.

Tooru had held her as she cried and when she finally cried herself out, she saw that he had cried along with her. He couldn't apologize, not for being who he was, and they both knew that if he had tried, Umi would have been furious. Instead, he tried to comfort her and tell her that he was sure there were people that liked her for being her and she was going to make friends that didn't want anything to do with him.

Umi hadn't but she never told him. He would have been devastated.

Eventually, she had earned herself a reputation – and not a good one. Most of her classmates avoided her completely and she had heard herself referred to as the "bad luck Oikawa" more than once. The "troubled Oikawa".

There was only one person she had come across in junior high that didn't compare her to her brother –and she was pretty sure that was only because he didn't know that Tooru _was_ her brother. In her second week of classes in her first year, Umi had come across the perfect spot to eat lunch. It was surrounded by trees and tucked just out of the way from the school. The only issue was that someone else was sitting there.

It took a week for Umi to realize that the dark haired boy would merely sit under the far tree, eat his food, and leave. He never had anyone sit with him. He never looked as if he was waiting for anyone to show up. He didn't bring a book or any homework. He just sat there, ate, and left.

So, she decided that it should be okay for her to do the same. She moved quickly that first time, getting there before the boy and sitting under a tree that was the furthest away from where he usually sat. She propped a book on her knees and kept her eyes down as she began to eat her food. She had just gotten situated when the boy appeared. He froze at first and Umi could feel his eyes drilling into the side of her head. After a few seconds of silence, it seemed as if he decided to just continue on with his routine and he moved toward his usual tree and the two ate in silence.

This continued throughout the school year. They both sat there during lunch, neither saying a word and neither being annoyed by the company. Against all common sense, Umi felt herself be drawn toward the quiet boy. He no longer left as soon as he finished eating. A few times, he asked Umi what she was reading and the two would discuss it. He wasn't very intelligent, not in the traditional sense, but he was always able to catch on to what she was talking about after a little explaining. He was blunt. More than once, Umi found herself reconsidering things that she ranted to him about with just a few words from him. He wasn't a complex person – things that others (namely: her) would overthink, he would look at from a simple angle. It was…different than she was used to. By the end of her first year, she wondered how she had fallen for a boy she didn't even know the name of.

It wasn't until her second year that Umi realized the boy was on the volleyball team. She had avoided the games her first year, knowing that the third years would have annoyed her about Tooru, but had decided that the current third years (who would have been first years when her brother was still in the school) most likely wouldn't bother her if she attended a game. She had been surprised when she saw the boy she sat beside at lunch playing – even more surprised when she saw how good he was. Oh, he wasn't anything compared to her brother. Not yet. But he would be.

She also found out his name during those games. Kageyama Tobio. The second she realized that the dark haired boy was the same person her brother had complained about constantly during his third year, the same person that she had heard Tooru and Iwaizumi arguing about, Umi had known she could never tell her brother who she sat with at lunch every day. Couldn't tell him that the hated Kageyama was the same boy she had found herself having her first crush on. So, she didn't. She hadn't even let Tooru know she knew who the other boy was.

She continued to sit in that same spot her third year, but this time she sat alone. Kageyama Tobio had graduated the year before. Still, it didn't stop her from getting information on the boy. She heard his name often, more often than she would have liked. Her brother really could be petty and it seemed that Kageyama brought it out of him.

By the time she graduated Junior High, Umi was completely set against going to Aobajosai. From the comments she had heard from Iwaizumi and some other friends of her brothers, things would be even worse there than they had been at Kitagawa Daiichi. She had considered going to Shiratorizawa – she was pretty sure she could pass the entrance exam – but even she knew that Tooru would take that worse than if she attended Karasuno.

Plus, there was a plus to Karasuno.

One she wasn't going to tell her brother about.

There was something that she wanted to do – something that she had wanted to do for some time but couldn't make herself do at Kitagawa Daiichi. Not while she was in Tooru's shadow. At Karasuno – well, she was well aware that she would still be compared to her brother, but not in the same way.

From what she had heard, there wasn't really any love lost between her brother and the Karasuno volleyball team.

"Yachi Hitoka?" Umi asked softly as she came up to a small, blond haired girl that she was sure she recognized.

The girl in questioned yelped loudly as she jumped, turning toward Umi with wide eyes. "Ye-yes?"

Umi bowed, "I am Oikawa Umi, first year. I was hoping I could talk to you about becoming a manager for the volleyball team."

The girls eyes grew impossibly wider, "Oh! I mean – I didn't think that anyone would – I, uh….sure?"

Well, that was easy enough. Umi smiled softly, "I have been interested in volleyball for a long time, Yachi-sempai. I thought that, with Karasuno once again being considered a powerhouse, you might like the help."

Yachi waved her hands around widely, shaking her head. "Oh, please, there's no need to call me that! And, yes! That would be great! I hadn't thought anyone would be interested, but I would love the help! You said you like volleyball? I knew nothing about it until last year when I – sorry, what was your name?" She cut herself off, a frown appearing between her brows.

Yeah, Umi had been expecting this. "Oikawa Umi, Yachi-san."

"Oikawa- as in…"

"Tooru is my older brother," Umi stated flatly. She tried to keep her face blank when she saw the brief look of panic overtake the older girl. _Good lord, Tooru, what did you do?_

"Oh! Well, um, I mean – you can still be manager, of course! But the guys…well, they aren't exactly…fans…?"

Umi felt herself crack and laughter began to leak from her mouth. She saw Yachi's mouth drop in shock as Umi began to laugh loudly. "I – I'm sorry!" Umi finally gasped out, brushing her right hand under her eyes to make sure no tears escaped. "I just – have never heard it put like that before!" she continued to laugh, ignoring the looks being thrown her way by various people. "I would like to help you, Yachi-san."

A smile crossed the other girls face at the words. "Great! At practice tonight, I'll introduce you! The first year boys will start tonight too, so it's a great time!"

Umi bowed once more, "Thank you. I will be there."

It took longer than she would like for her to find the gym. By the time she stepped foot inside, there were already a line of boys standing beside the court with another group in front of them. Kageyama was in that group, his eyes scanning over the line of boys in front of him. Kumi swallowed hard when she saw him. He had grown in the past year. Yachi smiled at her from beside the net and Kumi quickly made her way over toward the older girl, hoping none of the boys had noticed her slipping in. "Sorry, I got a little turned around."

"It's fine! We're getting ready to do introductions!" Yachi told her, a clip board in her hand.

"I am Kita Masaaki from Nagamushi Junior High," the first boy in line said, bowing his head. He looked to be one of the tallest in the room, only shorter than a tall blond with glasses. Umi thought he was probably close to Kageyama's height.

"Handa Ichiro from Izumitate Junior High," the next boy intoned quietly. From her spot, Umi could barely hear him. He was much shorter than the first, his dark hair only coming up to the other's shoulder.

The third boy smiled brightly and jumped from one foot to the other, "Hello! I'm Morikawa Takumi from Amemaru!" This boy waved toward the tall blond and another boy that was standing beside him with floppy brown hair and freckles. The blonde rolled his eyes but freckles waved with a small smile. Probably went to the same school.

The last boy had barely opened his mouth when one of Karasuno's members, a tall, bald boy, jumped forward and grabbed the other around his shoulders and cheered loudly. "Toma! I didn't know you would be here!"

"Tanaka-sempai –" the boy started.

"You should have-"

"Tanaka!" One of the Karasuno members said loudly, his eyes narrowing. Umi thought that this must be the captain. "Let him introduce himself."

The bald boy, Tanaka, Umi assumed, scowled but let go of the last boy. The boy bowed his head toward the captain, though Umi wasn't sure if it was to show thanks or to hide his bright red face. "Uh, I'm Toma Yoshio from Oujitsu."

"Nice to meet all of you," the captain said with a smile. "I am Ennoshita Chikara, Captain, and Wing Spiker."

"Tanaka Ryunosuke, third-year!" Baldy jumped in quickly, "Ace and Wing Spiker!"

"Nishinoya Yuu, third-year!" Was said. It took Umi a moment to realize that the words came from the shortest person in the room. She couldn't tell just how short he was because she was pretty sure his hair added a few cm. "Libero!"

Ah, Tooru had mentioned him.

Not nicely but just being mentioned from her brother was something in itself.

"Third-year Kinoshita Hisashi," the next said with a small grin, "Wing Spiker and Pinch Server."

"Third-year Narita Kazuhito. Middle blocker."

"I'm Hinata Shoyo!" Wow, okay. That was a little…loud for Umi's tastes. The boy, who was almost as short as Nishinoya, was jumping high enough that Umi had to blink in shock. Oh. That must be… "Middle blocker!"

Yep. Bet that was the "chibi-chan!" Tooru always complained about.

"I'm Yamaguchi Tadashi, second-year," This was said from the freckled boy who smiled nicely at the first years. He rubbed the back of his neck awkwardly, "Uh, Pinch Server and Middle Blocker."

There was a moment of silence and every eye was fixated on the two remaining people in line. Those two, however, seemed to be staring at one another. Umi wondered if it was some weird power play she didn't understand.

The two boys consisted of Kageyama and the tall blond. "Oi! One of you go!" The captain finally snapped.

Umi watched as Kageyama scowled and turned toward the first years, causing the blonde to smirk broadly in victory. "Kageyama Tobio, second-year, Setter."

"Tsukishima Kei, second year, Middle blocker," the blonde finally said, that smirk still on his face.

"Right, this is-" the captain broke off as he motioned toward Yachi, "uh, sorry? Yachi, who is…?"

"Oh! Sorry, Ennoshita-san! I should have mentioned earlier! This is Oikawa Umi, she'll be starting today as a second manager!"

Umi forced herself to keep eye contact as every single active member of the team stared at her. Some had their mouths hanging open, like Tanaka and Nishinoya. Some were scowling, like Tsukishima. Hinata didn't seem to know what to do as his head twisted frantically to look at various members. Umi didn't dare look toward Kageyama. She wasn't even sure if the second-year would remember her, but if he did, she didn't want to see the look on his face. It wasn't her fault he had never asked her what he name was!

"Oh, um, welcome to the team! Thank you for helping us!" Ennoshita finally said, obviously getting over his shock and giving her a small smile.

Umi smiled back and bowed her head, "Please take care of me."

Hinata seemed to break out of his shock and he bounded forward. "Hi! Oikawa? Are you related to the Great King?"

 _You have got to be kidding,_ Umi thought. "Sorry, Hinata-sempai, are you the reason he keeps calling himself that?"

There was a titter of laughter from the group but Hinata just nodded as he smiled brightly. Umi suddenly felt like she was standing out in the sun. "Yeah! He taught Kageyama and they call Kageyama the King-"

"Shut up, dumbass!"

And then Kageyama was there, gripping the back of Hinata's shirt and pulling him away from the girls. "Don't call me that!" He turned, ignoring the wailing Hinata was doing. His eyes snapped to Umi's and for the first time, she noticed that his eyes were a brilliant blue. She swallowed. "Oikawa is?"

"Uh, my brother," Umi admitted and she watched as Kageyama's neutral face twisted just slightly.

"You never said-"

"You didn't ask."

"Well," came a drawled response as Kageyama scowled fiercely. Umi tore her gaze away and looked toward the now smirking blond. Tsukishima, she believed. "This should be interesting."


End file.
